1. Field of the Invention
This invention relates to a liquid crystal electrooptic memory device using ferroelectric liquid crystal.
The liquid crystal electrooptic memory device of the invention can be used in a liquid crystal display, an optical computer, an optical printer, and the like. Other field of possible application include a liquid crystal information display panel, a liquid crystal printer, an electrophotographic copying machine, an optical information processing unit, an optical neuro-computer, an optical disk etc.
2. Related Art Statement
As compared with regular nematic devices, ferroelectric liquid crystal electrooptical memory device (FE-LCD) has outstanding features (N. Clark and S. Lagerwall: Applied Physics, Lett. 36 (1980) 899.); namely,
(1) memory characteristics, especially bistability, and
(2) high-speed response in the order to 10-100 .mu.S.
However, production of test models of such memory device encountered with the following short-comings and difficulties that hampered practical use of such memory device.
(a) For a memory device having an area of several tens to several hundreds of square centimeters, it is difficult to achieve high bistability in a uniform manner throughout the entire area.
(b) Molecular orientation tends to be imperfect, and the display sometimes becomes defective.
(c) Gray-scale display, which is an important requirement for application to almost all the information display means, is impossible.
The above shortcomings and difficulties are common problems for all the researchers and development engineers in this field throughout the world. In addition, there is a need for the following function.
(d) There is no practical method available for storing planar optical information, e.g., picture information, in liquid crystals by simply directing such optical information onto the liquid crystals.